(19)
(11) EP 2 161 407 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
21.03.2012 Bulletin 2012/12

(43) Date of publication A2:
10.03.2010 Bulletin 2010/10

(21) Application number: 09176252.6

(22) Date of filing: 12.04.2005
(51) International Patent Classification (IPC): 
G01C 19/56(2012.01)
G01C 21/16(2006.01)
 E21B 47/022(2012.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR

(30) Priority: 13.04.2004 US 823091

(62) Application number of the earlier application in accordance with Art. 76 EPC:
05744288.1 / 1735592

(71) Applicant: Gyrodata, Incorporated
Houston, Texas 77043-3115 (US)

(72) Inventors:
  • Ekseth, Roger
    N-7081, Sjetnemarka (NO)
  • Uttecht, Gary, William
    Houston, 77095 (US)

(74) Representative: Morris, Jonathan Paul 
Urquhart-Dykes & Lord LLP Midsummer House 413 Midsummer Boulevard
Milton Keynes MK9 3BN
Milton Keynes MK9 3BN (GB)

   


(54) Measuring borehole survey tool orientation using microgyros


(57) A system and method for determining an orientation of the survey tool within a borehole utilizes a survey tool including a plurality of rotation sensors each having a sensing axis and a direction of least acceleration sensitivity. The plurality of rotation sensors are arranged with their sensing axes generally parallel to one another and with their directions of least acceleration sensitivity generally non-parallel to one another. The survey tool further includes a controller adapted to calculate a weighted average of the detected angular rotation rates from the plurality of rotation sensors. The weighted average includes the detected angular rotation rate of each rotation sensor about its sensing axis weighted by the detected acceleration along its direction of least acceleration sensitivity.







Search report